The Fajr prayer
When to Perform the Fajr Prayer
Al-Fajr al-Sadiq, the true Fajr, is the first light that spreads across the horizon. Today, this phenomenon can only be observed in a few regions of the Earth. As humans harnessed electricity, and stars disappeared due to artificial light, the first light of Fajr was also obscured by our lighting. In most regions, it simply does not get dark enough to recognize this fine light on the horizon. This led many, who no longer know the true night, to stray. And so, everyone reports a different angle for calculating Fajr. The angle for Fajr has been known for more than 1000 years. It is at 18 degrees. And some were able to recognize it at 19 degrees. And astronomers said: Anyone who claims the angle is lower than 18 is saying something abnormal.
Scholars and Astronomers on the First Light of Fajr
The astronomer Al-Battānī said in the year (317 H) in the twelfth chapter of Kitāb az-Zīj on the making of the astrolabe (a tool for astronomical measurement): "If you want to set the arcs (muqantarāt) for the appearance of the dawn (ṭuluʿ al-fadschr) and the disappearance of the evening twilight (maghīb al-shafaq), place Capricorn (ra's al-jady) at eighteen in the arcs and mark on the counterpart the circle of Cancer (madār ra's al-sarṭān) as a sign. Then place Aries (ra's al-ḥamal) on that arc and mark on the counterpart. After that, place Cancer (ra's al-sarṭān) on it and mark on the counterpart. Then look for a midpoint that brings the three signs together for you, and draw a line over them. Then do on the other side what you did to their counterparts, so the arc in the east is the arc of the rise of dawn (ṭuluʿ al-fadschr) and the one in the west is the arc of the disappearance of the evening twilight."
The astronomer al-Bīrūnī (440 H) wrote in his book al-Qanoon al-Masoudi: "... and that is the dawn (Fajr), which has three types: The first is pointed, elongated, upright, known as the false dawn (Al-Fajr Al-Kadhib) and also called 'wolf's tail' (Dhanab al-Sarhan), and nothing of the religious laws (Shari'a) or the official customs is associated with it. The second type is flat, spreads across the horizon, round like a half-circle, with which the world is illuminated, under which animals and people gather for their habits, and the conditions for worship are met. The third type is a redness that follows and precedes the sun, and it is like the first in terms of the religious law ... and depending on the need for dawn (Fajr) and evening twilight, scholars of this science made their observations and derived from it the laws for the time, that when the sun sinks below the horizon and this amounts to eighteen parts, this is the time of the beginning of the dawn (ṭuluʿ al-fajr) in the east and the time of the disappearance of the evening twilight in the west, and because it is not separated but rather mixed (Comment: Meaning that Al-Fajr Al-Kadhib and Al-Fajr As-Saadiq are mixed and some could not recognize the beginning and the end), there was disagreement in this law, so some saw it as seventeen parts."
The astronomer Ibn al-Zarqālah (493 H) said in the forty-ninth chapter on the knowledge of twilight (al-shafaq) and the beginning of Fajr (ṭuluʿ al-fajr) in one of his letters: "You look at the sun, and if it has a northern inclination, then set the end of the Alhidade (rotating measuring device for angles) at the height of Aries (al-ḥamal) in your country at a quarter of the height, then remove the crossbar from the center of the plate to the side of the sign eighteen... What remains then is the time the firmament (al-falak) turns from sunset to the end of the twilight and likewise from the beginning of Fajr (ṭuluʿ al-fajr) to sunrise."
The great astronomer Nasir ud-Din at-Tusi (672 H) stated, after distinguishing between the false Fajr (al-fajr al-kadhib) and the true Fajr (al-fajr as-sadiq): "It was determined through observation (al-rasd) that the beginning of Fajr (awwal al-fajr) and the end of twilight (akhir al-shafaq) are the times when the sun is eighteen degrees below the horizon in terms of its altitude circle (da'irat irtifā'ihā)."
The astronomer Abu al-Hasan Ali ibn Ja'far ibn Ahmad ibn Yusuf ibn Baas al-Aslami (693 H) said: "The ninth chapter on the knowledge of the height of a star for the beginning of Fajr (ṭuluʿ al-fajr) and the disappearance of the twilight (al-yafaq) is based on a circle of 18 from the east for the twilight (al-shafaq) and from the west for the Fajr etc." (Comment: Since the sun is not visible, it is measured based on the height of a visible star)
The astronomer al-Qadi Zada (840 H) said in his commentary on al-Jaghmini's summary of astronomy: "It was found through experience that the beginning of the morning (awwal as-sabah) and the end of the evening twilight (akhir al-shafaq) only occur when the sun is eighteen parts (degrees) below the horizon."
Abu Zaid Abd ur-Rahman ibn Omar as-Susi al-Bu'aqili, known as Ibn al-Mufti (1003 H), said in the section on the times of the disappearance of twilight (al-shafaq) and the beginning of Fajr (ṭuluʿ al-fajr) and their respective stages: "It is important to know that the disappearance of the twilight (al-shafaq) corresponds to the beginning of Fajr (ṭuluʿ al-fajr), and that is when the sun is eighteen degrees below the horizon."